BOSTON (Reuters) - An “application glitch” led some Vanguard Group clients to see an inflated account balance displayed on their Apple mobile devices, a spokeswoman said - a hiccup that left at least one user cheering the apparent extra funds.

The issue did not affect clients’ actual balances or transactions, the spokeswoman for the index fund manager, Katie Henderson Hirt, said on Monday.

She added it was seen by people using Vanguard software applications on their iPhones, iPads or iWatches. Vanguard expected to have the issue fixed on Monday evening, she said.

Asked how many devices were affected, Hirt said the impact was a “modest number overall.” On average just 16 percent of logons to vanguard.com come from an Apple device, she said, and of those about 11 percent visit the personal performance page where they would have seen the inflated balance.

The problem related to the fact that Friday was the last trading day of April, she said. While the issue was not seen before, she said it was not caused by hacking.

One user of the app, Peter Lanphear of Bergen, New York, flagged the problem on Twitter on Monday and said in a followup conversation that he first noticed on Sunday that the app displayed a balance roughly $21,000 higher than it should have been, double the correct number.

Told it was too bad he could not keep the extra money, Lanphear replied “That’s what I said to them lol.”